text: define([], function () {
      'use strict';
  
      function factory(config, params) {
          // Heartbeat
          var heartbeat = 0,
              heartbeatTimer,
              runtime = params.runtime,
              interval = config.interval || 100;
  
          function start() {
              heartbeat = 0;
              heartbeatTimer = window.setInterval(function () {
                  heartbeat += 1;
                  runtime.send('app', 'heartbeat', { heartbeat: heartbeat });
              }, interval);
          }
  
          function stop() {
              if (heartbeatTimer) {
                  window.clearInterval(heartbeatTimer);
              }
          }
          return {
              start: start,
              stop: stop
          };
      }
  
      return {
          make: factory
      };
  });